This invention relates to a composition and a methods for treating synthetic or semi-synthetic fiber textile materials such as yarns, fabrics and the like for modifying their surface properties.
Synthetic and semi-synthetic fibers such as polyester, polyamide, acrylic, polyolefin, and cellulose acetate fibers have become widespread over various natural fibers including cotton, wool and silk in their production and consumption. However, there still exists a need for improving certain properties. They have relatively inert and dense surface and internal texture and exhibit poor dyeability, hygroscopicity, adhesiveness and the like. An enormous amount of attempts has been made and known in literatures to improve these properties but most of them have been proven unsatisfactory in commercial practice.
For example, polyester and polyamide fibers may be imparted with water-absorptive properties by post-treating with polyoxyethylene compounds, but this treatment has certain disadvantages including decrease in color fastness particularly frictional color fastness of the resulting products when dyeing with disperse dyes. In addition, this treatment is not effective to give the fibers with substantial moisture-adsorptive properties.
Since polyester fibers have a dense texture and consit of a chemically inert polymer material, they are not dyeable with conventional anionic and reactive dyes. They may be dyed only with disperse dyes requiring a temperature as high as 130.degree. C. or higher. It is known to improve the dyeability of polyester fibers by copolymerizing the polymer material with an anionic group-containing dibasic acid component or polyoxyethylene based glycol component in order to enable the use of cationic dyes or boiling dyeing methods. However, these approaches must suffer from certain disadvantages such as the use of relatively expensive raw materials and decrease in strength and other physical properties. The dyeing conditions of these modified fibers still require a temperature as high as 100.degree.-120.degree. C.
Chemically inert surfaces and dense texture of synthetic fibers such as polyester and polyolefin fibers also present a problem of poor adhesive strength to rubber or other elastomers when used as a reinforcement of pneumatic tires, conveyer belts, synthetic leather and the like. For example, tire cord is conventionally treated with resorcinol-formaldehyde-latex (RFL) prior to embedding into rubber. Since synthetic fibers generally exhibit a poor affinity to RFL, various pre-treating methods have been proposed but none of them has been proven completely satisfactory.
In the U.S. patent application Ser. No. 771,758, filed Sept. 3, 1985 and assigned to the assignee of this application (now U.S. Pat. No. 4,629,774), we have disclosed a composition for surface-treating synthetic fiber fabrics comprising an aqueous solution or dispersion of a thermally reactive polyisocyanate-adduct of hydroxyalkylated polysaccharide having at least one blocked isocyanate group. We have now discovered that similar products may be obtained starting from intact polysaccharides and their derivatives other than hydroxyalkyl ethers and/or using various reactants other than those described in said application.